This application relates to an improved airfoil, wherein mate faces between adjacent airfoils are contoured to optimize cooling air flow between the mate faces.
Various components in a gas turbine engine have an airfoil shape extending outwardly from a platform. One example is a turbine blade, which typically includes a platform, with an airfoil extending above the platform. The airfoil is curved, extending from a leading edge to a trailing edge, and between a pressure wall and a suction wall.
The turbine blade can become quite hot during operation of the gas turbine engine. Thus, cooling circuits are formed within the turbine blade to circulate cooling fluid, typically air. A number of cooling channels extend through the cross-section of the airfoil, and from the platform outwardly toward a tip. Air passes through these channels, and cools the turbine blade.
Many distinct types of cooling circuits are provided within the airfoil, and associated structures such as a platform, the root, etc. As known, a number of turbine blades are mounted to be circumferentially spaced. Leakage air is allowed to flow between a leading face of the platform, a trailing face of the platform, and on mate faces between adjacent platforms. This air cools the platforms, and allows the airfoils to better survive in the harsh environment of the gas turbine engine.
The platform has side edges that define mate faces. The cooling air flow between the mate faces has been directed by the gap between the mate faces. The gap is parallel to the mate faces, and the mate faces have traditionally been parallel to a groove within the root such that the blade can be more easily mounted to a rotor.
Applicant has determined that, for various reasons, providing cooling air flow from a gap between generally straight edges of a platform, does not optimize this cooling air flow. Instead, applicant has recognized that there are hot spots on the platform due to several features that are not best addressed by the prior cooling air flow.
In at least one prior art airfoil, the platform side edges are defined by a pair of straight sections. This was to allow the use of a platform having an edge extending on an angle that might otherwise intersect with the airfoil. This has not been utilized to address local hot spots.